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CVE-2026-64317

isofs: bound Rock Ridge symlink components to the SL record

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, and 2 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

Summary

In the Linux kernel, the following vulnerability has been resolved: isofs: bound Rock Ridge symlink components to the SL record get_symlink_chunk() and the SL handling in parse_rock_ridge_inode_internal() walk the variable-length components of a Rock Ridge "SL" (symbolic link) record. Each component is a two-byte header (flags, len) followed by len bytes of text, so it occupies slp->len + 2 bytes. Both loops read slp->len and advance to the next component, and get_symlink_chunk() additionally does memcpy(rpnt, slp->text, slp->len), but neither checks that the component lies within the SL record before dereferencing it. A crafted SL record whose component declares a len that runs past the record (rr->len) therefore triggers an out-of-bounds read of up to 255 bytes. When the record sits at the tail of its backing buffer - for example a small kmalloc()ed continuation block reached through a CE record - the read crosses the allocation; get_symlink_chunk() then copies the out-of-bounds bytes into the symlink body returned to user space by readlink(), disclosing adjacent kernel memory. ISO 9660 images are routinely mounted from untrusted removable media - desktop environments auto-mount them (e.g. via udisks2) without CAP_SYS_ADMIN - so the record contents are attacker-controlled. Reject any component that does not fit in the remaining record bytes before using it. In get_symlink_chunk() return NULL, like the existing output-buffer (plimit) checks, so a malformed record makes readlink() fail with -EIO rather than silently returning a truncated target; in parse_rock_ridge_inode_internal() stop the inode-size walk.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: partial

  3. Record last updated

Affected versions

  • Linux Linux

    From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 1015e1c4b2fadd9c09704e24738e46598778c869; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 36fe7d25dbc40da0c6b1dd4513a4f69ac6164eee; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in a22cb6bb54dc167047ea9e70d97dfbc2c15649e3; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in b736b12108fd116c41777628f5a333791604df26; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 6bf41db09ef935d76fcc84ccf213b42c18de95ee; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in b5699642640d6cff357638738c5293985cd5a53d; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 9830725078c8483c6831ec10222ae724806ea36b; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 5fa1d6a5ec2356d2107dead614437c66fa7138b1

  • Linux Linux

    2.6.12

  • KernelLinux

    From 2.6.12 · fixed in 5.10.261; From 5.11.0 · fixed in 5.15.212; From 5.16.0 · fixed in 6.1.178; From 6.2.0 · fixed in 6.6.145; From 6.7.0 · fixed in 6.12.96; From 6.13.0 · fixed in 6.18.39; From 6.19.0 · fixed in 7.1.4

References 8

git.kernel.org